The skin consists mainly of three layers, namely, starting from that closest to the surface, epidermis, dermis and hypodermis.
The epidermis makes an important contribution to protection of the skin and maintaining its proper function.
Ageing and photo-ageing of the skin and the associated changes may be manifested in various ways, among which we may mention:                loss of firmness and elasticity owing to tissue loss at the level of the epidermis and/or dermis;        loss of radiance owing to reduction of the microcirculation and slowing of cellular renewal at the level of the epidermis;        appearance of pigmented spots; and/or        dry skin resulting from a decline in the barrier function of the stratum corneum and slowing of epidermal renewal.        
There is therefore a need to provide a polyfunctional active agent that can act on a set of causes of changes to the skin due to ageing and/or a change in the physiological mechanisms connected with ageing.
Now, the applicant has found that an alcoholic extract of aerial parts of Solidago virgaurea subsp. alpestris, obtained by a particular method, displays, through stimulation or inhibition of physiological mechanisms, interesting effects with respect to skin ageing, and the pigmentation and microcirculation of the skin. In fact, as demonstrated with examples, the alcoholic extract of aerial parts of Solidago virgaurea subsp. alpestris according to the invention has interesting cosmetic properties: it is able to combat ageing of the skin, notably through its anti-MMP3 and anti-MMP9 effects; it has antioxidant properties; it activates the microcirculation in the skin; and it has a depigmenting action. The extract according to the invention also has an anti-ageing effect on the skin, as it can delay replicative senescence, it prevents the transition of papillary fibroblasts into reticular fibroblasts, and reduces the expression of senescence markers.
Therefore, according to a first aspect, the invention relates to an alcoholic extract of aerial parts of Solidago virgaurea subsp. alpestris, obtainable by a method comprising the following steps:                a) extracting the aerial parts of Solidago virgaurea subsp. alpestris, with at least one alcoholic solvent;        b) incubating the mixture obtained in a) for at least 10 h;        c) filtering the incubated mixture obtained in b); and        d) removing the solvent from the filtrate obtained, and then final dilution in another alcoholic solvent.Thus, in the present application, such an extract is called extract according to the invention.        